Solid adducts

Another chemical route is by decomposition of solid adducts of ozone with triaryl and other phosphites at subambient temperatures ... 

Chemical Reactions. It burns with a luminous flame and is readily expld (Ref 2). It is reduced with Zn dust and Na hydroxide to dimethyl hydrazine (Ref 2). Action of coned HC1 forms methylhydrazine and formaldehyde (Ref 2). Treatment in anhyd eth with Na metal forms a solid adduct which gives dimethylhydrazine on addn of w (Ref 4). For a review of thermal and photochem reactions see Ref 8 Explosive Limits. In mixts with air the crit press at which exp] occurs varies inversely with temp betw 350 and 380° (Ref 6)... 

Trimethylamine and gaseous S2O react at -30 °C and low pressure to the yellow solid adduct Me3N-S20 which sublimes in a high vacuum (probably with dissociation in the gas-phase and recombination on condensation). This adduct is soluble in organic solvents it is analogous to but less stable than the colorless Me3N-S02 [51]. 

Finally, it has recently been shown207 that some silenes can add sulfur or selenium to give silathiiranes 110, as confirmed by a crystal structure, or silaseleniranes 111, respectively (Eq. 37). Only sterically crowded silenes such as 112 gave stable solid adducts, and in the case of the selenium species the adducts visibly decomposed in the solid state over a few days. 

Diphenylketimine forms an unstable solid adduct with trimethylborane, which, above 160 °C, slowly eliminates methane under formation of (diphenylmethyl-eneamino)methylborane 4°). 

Solid adducts between (C43) and (C6H5)2C=NH BF3 is sufficiently stable to withstand vacuum sublimation at 120 °C. Attempted preparation of corresponding BC13 derivatives led only to (diphenyl-methyleneimino)boranes 41). Recently, additional imine-trifluoroborane adducts have been described 44h they are listed in Table 8. 

Dichloromethylenephenylamine and dichloromethyleneethylamine yield solid adducts 23) upon treatment with trichloro- or tribromoborane. 

Anilines are converted into nitrosoarenes ArNO by the action of hydrogen peroxide in the presence of [Mo(0)(02)2(H20) (HMPA)]224, whereas catalysis of the reaction by titanium silicate and zeolites results in the formation of azoxybenzenes ArN (0)=NAr225. Azo compounds ArN=NAr are formed in 42-99% yields by the phase-transfer assisted potassium permanganate oxidation of primary aromatic amines in aqueous benzene containing a little tetrabutylammonium bromide226. The reaction of arylamines with chromyl chloride gives solid adducts which, on hydrolysis, yield mixtures of azo compounds, p-benzoquinone and p-benzoquinone anils 234227. 

The 1,4-addition of selenophenols to cycloalkenones proceeds smoothly under the same conditions used in the thiophenol addition (see Section V) (eq. [18]). Although the e.e. of the products is 40 to 65%, compared with the 60 to 80% achieved in the thiol addition reaction, the solid adducts are readily purified to enantiomeric purity by crystallization (63). 

From these data, the heat of dissociation, AHa = 37.24 kcal mole , and the heat of formation of the solid adduct, JIfO/298 = —495.7 kcal rnole" were obtained. For the latter the literature value was corrected by using the more precise value of —35.9 kcal mole for the heat of formation of gaseous GlFgO (see Table VIII). The adduct melts under its own vapor pressure at 50.5°G 300). 

Figure 6.3. Apparatus for the reaction of alkali metals with carbonyl compounds and the separation of the solid adducts. [Adapted from Ref. 9.] A, separatory funnel in which the reaction is carried out B, cylinder with inert atmosphere C, perforated porcelain disc with filter paper D, entry of inert gas (H2 or CO2) from Kipp apparatus E, wash ether reservoir.

CH2)3NH2]2.H202 mw 150.26, N 18.64% crysts. HMDA reacts with aq or ethereal H202 to give a solid adduct... 

Problem 15.27 NaHSO, reacts with RCHO in EtOH to give a solid adduct, (a) Write an equation for the reaction, (b) Explain why only RCHO, methyl ketones (RCOCH,) and cyclic ketones react, (c) If the carbonyl compound can be regenerated on treating the adduct with acid or base, explain how this reaction with NaHSO, can be used to separate RCHO from noncarbonyl compounds such as RCHjOH. 

Aldehydes and Ketones. The best derivative from which an aldehyde can be recovered readily is its bisulphite addition compound, the main disadvantage being the lack of a sharp melting point. The aldehyde (sometimes in ethanol) is shaken with a cold saturated solution of sodium bisulphite until no more solid adduct separates. The adduct is filtered off, washed with a little water, then alcohol. A better reagent is freshly prepared saturated aqueous sodium bisulphite solution to which 75% ethanol is added to near-saturation. (Water may have to be added dropwise to render this solution clear.) With this reagent the aldehyde need not be dissolved separately in alcohol and the adduct is finally washed with alcohol. The aldehyde is recovered by dissolving the adduct in the least volume of water and adding an equivalent quantity of sodium carbonate (not sodium hydroxide) or concentrated hydrochloric acid to react with the bisulphite, followed by steam distillation or solvent extraction. 

Complexes of SB (73) are five-coordinate in solution and normally show no tendency to coordinate a basic ligand to form six-coordinate compounds.725 The formation of adducts depends on the chelate ring, as in (70). With electronegative groups in the aromatic ring, e.g. 5-N02salen (73 RI = R2 = H, R = 5-N02), electronic and CD spectra show hexacoordinate adducts, and solid adducts were obtained with py and DMSO.725... 

In (67 R1 = R2 = Me, R = H) with X = Br green or yellow complexes were obtained, according to the solvent used, with v(V=0) at ca. 980 and 900 cm-1, respectively.748 When X = C1, only the green-type complex may be obtained. The authors assume five-coordinate square pyramidal geometry for the green complexes and a chain structure -V=0 V=0 , similar to [VO(salnpn)], for the yellow complex. Solid adducts were isolated with 1-methylimidazole. 

In general, the stable thermodynamic products of ordinary flames have little worth, but many of the uncommon flames have products of value. The chlorination of hydrocarbons may be carried out in a flame process which was recently announced (A4). A most fascinating example is the formation of boron nitride from the flame reaction between diborane and hydrazine, two compounds which are ordinarily thought of as fuels (B2, VI). The stabilization of this flame depends upon the proper preparation of the premixed gases, since a solid adduct between the reactants prevents flame stabilization if the preflame residence time is too great. 

It is claimed that benzo[b]thiophone reacts with hexafluorophos-phoric acid in liquid sulfur dioxide, or with a mixture of anhydrous hydrofluoric acid and phosphorus pentafluoride, to give solid adducts, the natures of which have not been disclosed.395... 

The alkenes are distinguished from the alkanes by their solubility in concentrated sulphuric acid and their characteristic reactions with dilute potassium permanganate solution and with bromine. Characterisation may be based upon the determination of their physical and/or spectral properties. Characterisation by way of solid adducts with nitrosyl chloride has been quite widely used in the terpene field the preparation of adducts with 2,4-dinitrobenzenesulphenyl chloride is described below (see also Section 8.1.1, p. 1128). 

Tetraorganotin compounds, R4Sn, show weak acceptor properties and do not form solid adducts, with the possible exception of Me3SnCF3, which is reported (53) to form a 1 1 complex with hexa-methylphosphortriamide. Tetramethyltin, for example, has little or no tendency to form complexes with a wide range of solvents, (9) since the chemical shift changes are very small (Table V). 

Early investigations were based largely on the ability to separate solid adducts whose composition was determined by analysis. More recently spectroscopic techniques have been used and naturally, in view of the strong colours often produced, visible spectroscopy has proved popular. However this does not in general provide conclusive evidence of the species present. A big impetus to the study of these interactions... 

The 1 1 solid adduct of tetrathiafulvalene (TTF) and tetracyanoquin-odimethane (TCNQ) is the first-discovered molecular metal, which consists of alternate stacks each composed of molecules of the same type (Fig. 4.1.3). A charge transfer of 0.69 electron per molecule from the HOMO (mainly S atom s lone pair in character) of TTF to the LUMO of TCNQ results in two partially filled bands, which account for the electrical conductivity of TTF TCNQ. 

Arguments used to explain the isolation of one isomer over the other have typically been based upon the solid adducts, but this is unsatisfactory since many systems show the coexistence of both forms in the solid state. It has been shown that adducts can undergo isomerization in the solid state, e.g. SnX4D2 with X = Cl, D = DMF, DMA or DMSO and for X = Br, D = DMF or DMA were obtained from solution as the cis isomers, and converted to the trans form by heating1121. 

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